1. Field of the Invention
The present invention relates to a door weather strip including an attaching base part fitted to an attachment position of a peripheral edge of a door for a vehicle and a seal part extending in an outer peripheral direction of the door from the attaching base part.
2. Related Art
Ordinarily, a door weather strip is attached to a peripheral edge of a door for a vehicle (an automobile). The door weather strip includes an attaching base part fitted to an attachment position of the peripheral edge of the door and a seal part, integrally formed integrally with the attaching base part and having a hollow part. The seal part of the door weather strip is allowed to come into contact with a peripheral edge of an opening of the door of a vehicle body (an automobile main body) under pressure so that the opening part of the door and the vehicle body are sealed, when the door is closed.
The door weather strip includes the attaching base part and the seal part as described above, however, functions thereof are different depending on parts respectively. Namely, since the attaching base part is a part fitted to the attachment position of the peripheral edge of the door, an attaching form thereof is expected to be held for a long period of time. On the other hand, the hollow seal part is expected to be capable to follow the deformation when the seal part is pressed toward the peripheral edge of the opening of the door of the vehicle body.
However, usually, it has been difficult to realize, so to speak, opposite performances as described above at the same time. On the other and, a technique is proposed that an attaching base part and a seal part are made of different materials (for instance see JP-A-2009-96455.).
In this technique, the attaching base part is made of a sponge rubber material whose specific gravity is 0.2 or higher and lower than 0.45 and whose low stretch stress of 200 kPa or higher, and the seal part is made of a sponge rubber material that has a specific gravity of 0.45 or higher and 1.0 or lower and a low stretch stress of 120 kPa or higher and lower than 200 kPa.
However, in the technique described above, since a rate of the seal part is large and the specific gravity thereof is relatively large, it is hard to say that the technique described above satisfactorily meets recent demand for further weight reduction of door weather strip. Further, in the more technique described above, two extruders are required to be able to combine two kinds of materials together, so that a production device becomes more complicated.